Question

What constant do you need to add to each quadratic to complete the square?

1. x^2 - 4x = 0 16
2. x^2 - 8x = 6 4
3. 3x^2 + 18x = 24 9

Answer 1

3 x^2 + 18 x = 24 --> 9

x^2 - 8 x = 6 --> 16

x^2 - 4 x = 0 --> 4

Explanation:

Just finished this lesson.

Proof.

Answer 2

1. 4

2. 16

3. 9

Explanation:

Completing the square requires a quadratic in
`ax^2+bx=c` form. Once in this form, calculate
`((b)/(2))^2`.

1.
`((b)/(2))^2=((-4)/(2))^2=4`

2.
`((b)/(2))^2=((-8)/(2))^2=16`

3. Requires you divide everything by 3 first.

`(3x^2+18x)/(3) =(249)/(3) \\x^2+6x=81`

`((b)/(2))^2=((6)/(2))^2=9`